/*
 * Copyright 2010-2012 Susanta Tewari. <freecode4susant@users.sourceforge.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package bd.org.apache.commons.math.analysis.function;

import bd.org.apache.commons.math.analysis.DifferentiableUnivariateFunction;

/**
 * Identity function.
 *
 * @version $Id$
 * @since 3.0
 */
public class Identity implements DifferentiableUnivariateFunction {

    /**
     * {@inheritDoc}
     */
    @Override
    public double value(double x) {

        return x;
    }


    /**
     * {@inheritDoc}
     */
    @Override
    public DifferentiableUnivariateFunction derivative() {

        return new Constant(1);
    }
}
